A valve device is configured to switch between an open position and a close position by moving a spool with respect to a spool bore formed in the valve body. The open position allows passage of oil through a gap between two ports in the spool bore via a notch formed in a large-diameter portion of the spool from a small-diameter portion thereof. The close position blocks passage of oil between the two ports by the large-diameter portion. In this type of valve device, when oil passes through a gap between two ports formed in a spool bore with a spool arranged at an open position, a force (flow force) acts so as to make the spool return to a close position. As a result, a problem may be caused that an oil flow rate does not increase as intended.
Therefore, in the related art, there has been provided a valve device configured to change the direction of oil flowing in a port in a spool bore via a notch of a spool. The valve device can reduce a flow force acting to return the spool to a close position since the flowing direction of oil is changed with respect to a center axis of the spool (for example, refer to Patent Literature 1).